Diazo compounds are important carcinogens and carcinolytes. The objectives of the present research are to: (1) study transformations of heterocyclic diazo compounds, N-nitrosoureas, and their derivatives of present significance in cancer therapy, (2) investigate synthesis and the properties of diazo compounds, diazirines, and their analogs and derivatives as necessary to allow preparation of materials of improved carcinolytic activity, and (3) provide experimental quantities and/or laboratory methods for various agents so that their antineoplastic properties can be evaluated. The study will include: (1) determination of the thermal, photochemical, and displacement reactions of DTIC, DCTIC, and related diazo imidazoles, (2) synthesis and elaboration of the chemistry of 3-diazopyrroles and 2-diazopyrroles and their carboxamido derivatives, (3) preparation and study of the utility of diazothiapyrans and diazodihydropyridines in oncology problems, (4) synthesis of alpha-diazothiolcarboxylic esters and determination of their properties, (5) chemical transformations of 3-alkyl-l-(haloalky)-1-nitrosoureas of the BCNU and CCNU type, (6) preparation and elaboration of the properties of substituted diazirines, (7) synthesis of ethionine analogs such as 2-diazo-4-(methylthio)butyric acid and its variants, and (8) preparation of diazocyclopentadiene-2-carboxamide and diazocyclopentadiene-3-carboxamide and their triazene derivatives. BIBLIOGRAPHIC REFERENCES: Alpha-Alkoxyalkylidenetriphenylphosphazines as Ylide Reagents and as a Source of Alpha-Alkoxycarbenes, G.B. Merril and H. Shechter, Tetrahedron Lett., 4527 (1975). 9-Diazoxanthene and 9-Xanthylidene, G. Jones and H. Shechter, J. Amer. Chem. Soc., in press (1975).